1. Field of the Invention
The present invention relates to an image processing method and apparatus such as a copier, provided with functions of inputting and outputting an image, and in addition, capable of subjecting an inputted image to a predetermined process and outputting the image.
2. Description of the Related Art
In a digital copier which reads and outputs an image, the following well-known techniques are used: a technique of synthesizing a plurality of documents into a single document and outputting the single document; and an inserting and synthesizing technique of subjecting a masking process to an arbitrarily predetermined region of a document and thereby inserting another document into the document. Such a synthesizing technique as mentioned above is described in Japanese Unexamined Patent Publication JP-A 5-145735 (1993), for example. In this prior art, the user operates operating means such as an edit pad to set a trim region in an image from which trim region an image is extracted. The extracted image is inserted into a mask region in another image which is a base image, to be synthesized. By adding a twist to a method of specifying a mask region, it is possible to eliminate an unnecessary image region from an extracted image.
JP-A 5-145735 discloses elimination of an unnecessary image region by specifying a mask region. However, in the case of, for example, a hand-written note which is overwritten on a printed matter, it is difficult to definitely separate the note as a mask region, so that it is difficult to eliminate the note only by adding a twist to a method of specifying a mask region. Moreover, since it is necessary to prepare a display device and a terminal device such as operating means so that the user can specify a mask region, the overall apparatus tends to be upsized, and it gets hard to use the apparatus with ease.
Further, Japanese Unexamined Patent Publication JP-A 63-163678 (1988) discloses an automatic image checking apparatus for checking images of two objects, e.g., prints of seals. The automatic image checking apparatus extracts checking objects from the respective images on the basis of a portion common to the images of the two objects, and executes a checking process on the basis of the checking objects extracted from the respective images. At the time of extracting the checking objects, after the images of the two objects are mutually registered, an initial mask pattern is formed by considering a pixel density value of 1 or more to be 1 in the respective images while ANDing both the images, and a final mask pattern is generated by expanding the initial mask pattern. The images of the two objects are subjected to masking, respectively, by using the final mask pattern, with the result that the checking objects of the respective images are extracted. In JP-A 63-163678, a pixel density value of 1 or more is replaced with 1, so that the difference in density values of pixels, each of which has a pixel density value of 1 or more, is not reflected on extraction of a portion common to images of two objects therefrom.
Furthermore, Japanese Unexamined Patent Publication JP-A 5-231837 (1993) discloses a shape measuring method for working out the shape of a soldered part which is given to an electronic component on a packing board. In the shape measuring method, an angle of illumination to the soldered part given to the electronic component on the packing board is sequentially changed. At every predetermined angle, regular reflection light from the soldered part is picked up. For the purpose of eliminating an image of wiring or the like which is common to both images, data of the images shot at every predetermined angle are subjected to a process of subtracting one from the other. On the basis of data of the images obtained in the subtracting process, the three-dimensional shape of the soldered part is worked out. In JP-A 5-231837, the data of the images is subjected to a process of subtracting for each pixel as it is, so that the magnitude of the difference in pixel values is not reflected on elimination of an image common to both images.